Internal combustion engine



May 4, 1937. 1'. v. DILLSTRCM INTERNAL COMBUSTION ENGINE Filed Sept. 21,1935 3 Sheets-Sheet l 94 u z u w o 95/ 64 08 U //0 7 f C) /0,e-- QIINVENTOR I W W (,Qmw

M ATTORNEY May 4, 1937. r T. v. DILLSTRCM 2,078,934

INTERNAL COMBUSTION ENGINE Filed Sept. 21, 1933 3 Sheets-Sheet 2 LE IIINVENTOR J4)? EW-WOQAJM w ATTORNEY v to constant load operation.

Patented May 4, i937 NT "OFFICE INTERNAL COMBUSTION ENGINE 'llorbjiirnViktor Dillstriim, Stockholm, Sweden, assignor to Hesselman MotorCorporation, Ltd.,

London, England, a Britain corporation of Great Application September21, 1933, Serial No. 690,304

. in Sweden February 6, 1933 s Claims.

The present invention relates to internal com- :bustion engines. Moreparticularly the invention relates to multiple cylinder internalcombustion engines of the solid or airless injection type.

Still more particularly the invention relates to engines of the abovecharacter adapted to beoperated at loads of different value in contrastIn the operation of internal combustion engines of the airless or solidinjection type, particularly engines of the character in which ignitionis effected by a timed ignition device, it is highly desirablein orderto secure the most reliable ignition of small fuel charges to throttlethe air for combustion adniitted to the engine as well as to reduce theamount of fuel supplied when the engine'is operated in a rangecorresponding to loads less than full load. It is further desirable tomaintain a desired relation between the amounts of fuel and air admittedto the cylinders of the engine'throughout the range of operation inwhich the air is throttled, including operation at minimum load oridling operation of the engine.

-The degree of throttling. increases with decrease of load and thegreater the degree of throttling themore likely is proper combustion tobe disturbed by slight variations from the correct amount of airsupplied. Itwill be evident that at very light or idling load on theengine very slight errors in the amount of air admitted, while they maybe insignificant when considered from a standpoint of their absolutevalue, nevertheless' effect a'considerable variation in the rela-.

tive proportions of fuel and air forming the constituents of the chargesin the engine cylinders. Particularly in the case of engines forself-propelled vehicles it is difli'cult to secure the admisthrottledthe pressure in the combustion chambers of the engine at the time whenthe engine intake valves open may be equal to or higher than atmosphericpressure while the-pressure in the engine induction pipe or inletmanifold is considerably less than atmospheric pressure. As a result,exhaust gases. from the combustion chamber will flow through the intakevalves to the inlet manifold until the pressure difference is balanced,the flow being then reversed through the open inlet valves during thesuction stroke of the pistons. In such cases the result may be that someof the cylinders of the engine receive a charge comprising a relativelylarge' proportion of exhaust gases while other cylinders may receivecharges containing substantially nothing but fresh air. Under suchconditions it is obvious that satisfactory combustion of even I chargesin the several cylinders cannot be relied upon. 1

The present invention has for a general object the elimination ofdifliculties heretofore encountered in the operation of engines of thecharacter under discussion by eliminating the extreme sensitiveness ofoperation thereof when operated in accordance with previously knownmethods.

In accordance with the present invention, the air supplied to the engineis not throttled atidling load or at very low loads of the order ofidling "load'to the extreme degree which would" be required if all ofthe engine cylinders were operated at such loads,but by rendering one ormore of the cylinders of the engine inoperative to perform work at loadsbelow a predetermined value, the work necessary to operatethe engine atloads below such predetermined value is obtained from the remaining orworking cylinders,

which cylinders operate with better combustion than would be obtainedwith'all cylinders operating with the combustion air throttled to anex-. treme degree. If, for example, the engine were run idly with allcylinders in operation, it would 5 be desirable to throttle the air tosuch an extent that an over-rich mixture would be produced, in order toinsure as far as possible the reliable ignition of the charges under thevery low load operation conditions. Operation with an overrich mixtureis, however, undesirable for a num 'ber of reasons, and in accordancewith the present invention it is proposed to obtain steady and reliableoperation of the engine at low or idling load by operating it with avacuum in the inlet manifold of somewhat less value than that whichwould have to be maintained if all cylinders were maintained inoperation at such load. The extent to which the vacuum should be reduceddepends on a number of conditions, the most im-' portant of which is thenumber of cylinders which are cut out of operation, but which alsoinclude the design of the combustion'chambers of the cylinders, thecharacter of the fuel, and other factors. Preferably, the value of the.vacuum which it is desirable to employ with an engine running idly onall cylinders is ,reduced by approximately ten per cent in accordancewith the present invention, but the degree of reduction of thevacuum,may be as much as fifteen or twenty percent.

It may be stated, however, as a'general rule, that the ratio of air tofuel supplied to the cylinders at the time when one or more of the '10cylinders are cut out of action should as far as possible be maintainedin the cylinders that remain in operation. when the engine is operatedwith less than the total number of cylinders working.

The invention may be carried into effect "in many different ways, but itis preferable to cut out of operation those cylinders which are renderedinoperative by means automatically responsive, either directly orindirectly, to the movement of the member or members controlling thethrottling of the air supply. Furthermore, it is advantageous to renderthe desired number of cylinders inoperative in engines of the characterunder discussion by rendering inoperative a corresponding number of fuelpumps for supplying fuel-thereto. I

For a more complete understanding of the nature of the invention, whichincludes novel means for effecting the desired control as well be had tothe following description of the several forms of apparatus suitable forcarrying the invention into effect and illustrated in the accompanyingdrawings forming a part of this specification.

In the drawings:

Fig. 1 is a more or less diagrammatic end elevation, partly in section,of an engine provided with apparatus embodying the invention;

Fig. 2 is a side view partly in section and on an enlarged scale of thepump unit shown in Fig. l;

Fig. 3 is a section taken on the line 3-3 of Fig. 2;

Fig. 4 is a view on a larger scale of a preferred form of pressureresponsive means of the character shown in Fig. 1;

Fig. 5 is a view showing a different arrangement for controlling theenergizing of part of the apparatus shown in Fig. 1;

Fig. 6 is a} view showing a different arrangement of pressure responsiveapparatus for con trolling part of the structure shown in Fig. 1; and

Fig. 7 is a more or less diagrammatic perspec tive view showing stillanother form of apparatus for controlling the fuel and air supplied tothe engine in accordance with the invention.

Referring now more particularly to Fig. l, A designates the engine, thecombustion chamber of one of the cylinders thereof being indicated atIll. Fuel is injected into the cylinder by means of injection nozzle 12,and air is supplied to the cylinder through the usual intake valve (notshown) which is in communication with the inlet passage of the inductionpipe or manifold l6 which is adapted to supply air to the severalcylinders of the engine. Ignition is effected by the spark plugindicated at l8. The engine illustrated is adapted to be operated inaccordance with the method disclosed in U. S. Patent No. 1,835,490granted December 8, 1931 to K. J. E. Hesselman, but the presentinvention is not limited in its application to such engines. Control 75of the amount of air admitted to the manifold as the novel method ofoperation, reference may.

- the several cylinders by means of a pump unit indicated generally-at Band comprising a plurality ofpumps, one for each cylinder of the engine,the discharge passages of the several by means of pipes 24.

Turning now more particularly to Figs. 2 and 3, the pump unit Billustrated is that for a. sixcylinder engine, and comprises sixseparate plunger pumps, one of which is shown in section in Fig. 3.Sincethe construction of the pumps is identical, a description of one issuflicient. A pump chamber 26 is provided in a central casing part 28which is preferably in the form of an integral block and the pumpplunger'30 is mounted in a suitable barrel 32 retained in block 28 bymeans of the retainer member 34. Fuel is admitted to chamber 36 formedin the casing part 38 and flows from chamber 36 through the inletpassage 40 controlled-by the check valve 42 to the pump chamber 26. Fueldischarged from chamber 26 passes through passage 44 controlled by checkvalve 46 to the delivery pipe 24. A relief valve 48 seated by spring 50and adapted to be opened by contact of the inner' end of plunger 30prior to the end of the discharge stroke of the plunger provides forquick cut oif of the discharge of fuel, excess fuel from the pump chamher being returned to chamber 36 through passages 5l.

The pump plunger is moved outwardly on its suction stroke by means ofthe pump spring 52 and inwardly on its discharge stroke by means oftappet 54 actuated by cam 56 on cam shaft 58 which is mounted in thelower casing member 60. At its ends casing member 60 is provided withupwardly extending end walls 66a and 60b to which the block 28 is boltedat its ends.

Regulation of the length of the effective discharge strokes of the pumpplungers is effected by means of a rock shaft 62 having a plurality ofsleeves 64 mounted thereon, there being one sleeve for each pump. Eachsleeve 64 has an opening 66 providing an edge adapted to contact thelower face of collar 68 on the corresponding pump plunger 30. Each ofthe sleeves 64 is connected bymeans of a spring Ill to a pin at the endof an arm 12 fixed to shaft 62 by means of bolt 14, there being anopening in the sleeve 64 at the point where the arm 12 isbolted to theshaft. It will be evident that if shaft 62 is turned in clockwisedirection as viewed in Fig. 3, sleeve 64 will be turned therewith toeffect shortening of the stroke of the plunger on its suction stroke,and consequently shortening of the next ensuing discharge stroke. Thespring 10 is strong enough to hold sleeve 64 in contact with theabutment provided by the adjusting screw 16 on arm 12 against thecounter pressure of the pump spring 52, but is not sufficiently strongto effect movement of the pump plunger 36 inwardly against the pressurerequired to force fuel from the pump through the discharge passage tothe injection nozzle. This resilient connection provides againstadjustment to shorten the stroke of the pump plunger at the wrong timein the cycle of operation of the pump, for example, during a period ofthe pump pumps .being connected to the injection nozzles connected toshaft 02.

Q cycle'corresponding to the exhaust stroke of the cylinder with whichthe pump is associated.

For the purposeof rendering one or more of the pumps inoperative tosupply fuel to their respectively associated cylinders, a second shaftI8 is provided, similar to shaft 62, which has slidably mounted thereona number of sleeves corresponding in number to the number of pumps it isdesired to render inoperative. Sleeves 80 aresimilar in construction tosleeves 64 on shaft 62 and are connected to the shaft through the mediumof springs 82 and arms 84 in a manner similar to the manner in whichsleeves 64 are It will. be evident that turning of shaft I8 incounterclockwise direction may effect movement of the pump plungers withrespect to which sleeves-80 are associated to a position such that theseplungers are out of contact with their cooperating tappets 50 in allpositions of the latter. In the embodiment illustrated it will be seenfrom Fig. 2 that sleeve 60 of shaft 62 is associated with each of thepump 'plungers of the six-cylinder pump unit whereas only three sleeves80 are mounted on the shaft I8 for the purpose of cutting out pumps. Itwill be understood, of course, that while the three sleeves 80 are shownas associated with three adjacent pumps, the relation of the camsoperating thesepumps and the connections from these pumps to thecylinders of the engine are such that cutting 'out these three pumpsserves to cutout of operation three cylinders of the engine suitablyspaced with respect to timing in the cycle of operation of the engine asa whole.- Obviously, the number of pumps to be rendered inoperative maybe varied byvarying'the number of sleeves 80, but I prefer in mostinstances, in accordance with the present invention, to cut out ofaction half of the cylinders of the engine; While for purposesofillustration I have shown a. preferred form of fuel injection pump unit,it i will be understood that the specific details of i construction ofthe fuel supplying device form per se no part of the present inventionThe novel features of construction of the pump unit herein illustratedby way of example are disclosed and claimed in my'copending application,Serial No.

690,303, filed September 21, 1933, and the disclosure in s idapplication may be considered as incorporate herein.

Referring. again to Fig. l, the apparatus for carrying the inventioninto effect with the pump unit just described comprises a vacuumcylinder 00 in which is slidably mounted piston 88. Cylinder 86 providesa chamber 90 in communication with the atmosphere by way of port 92 andto which one face of piston 80 is exposed. The

opposite face of piston 88 is exposed to the pressure of theair in theintake passage M, which is in communication by way of connection 94 withthe chamber 96. A spring 98 in chamber 06 tends to move the piston 88upwardly as'seen in Fig. 1.

Piston 88 is connected by means of the lever arm turn shaft 62 inclockwise direction and effect shortening ofthe strokes of the pumpplungers 30. I 1

Actuation of the shaft I8 to effect cutting out of some of the pumps isin the present embodiment. effected electrically. The apparatus forperforming this function comprises a solenoid I00 the coil of which isconnected at one end to a terminal (preferably the positive terminal) ofa storage battery I02 or other source of electric current and at itsother end to an insulated contact I04 in the air inlet passage I4. The

remaining terminal of the battery I02 is grounded on the engine. Theplunger I06 of the solenoid is held in the position shown, when thesolenoid is not energized, by spring I08 acting on arm III! which isfixed to shaft I8, and when the solenoid is not energized, the partswill be in the position shown in Fig. 1, in which position the sleeves80 associated with shaft 'I 8 are-out of contact with their associatedpump plungers and consequently have no effect thereon. When the solenoidis energized the plunger I06 will move downwardly, efiectingcounterclockwise movement of shaft 10 as viewed in Fig. l, and causingthe pumps with which sleeves 80 are associated to be moved upwardly to aposition rendering these pumps inoperative to supply fuel.

Solenoid I00 is actuated by means of pressure responsive apparatuscomprising a slidably mounted contact pin IIZ. which-is held away fromthe contact I041 by means of spring N0,

the tension of which is preferably made adjust- .spring H0, pin H2 willbe moved into contact with the contact I00, thus closing the circuit inwhich the solenoid I00 is located and energizing the latter to turn theshaft I8 to a position effecting cutting out of v the desired number ofpumps.

In Fig. 4 I have shown in detail on an enlarged scale' a preferred formof pressure responsive apparatus for use in the arrangement shown inFig. 1 or similar electrically actuated arrangements, In thisarrangement the central portion of the diaphragm H6 is clamped betweenthe upper and lower plates I20 and IE2 and the upper casing part or capI20 is provided with an annular downwardly extending flange I20providing a seat adapted to contact the plate I20 when the diaphragm isin its upper position. thus providing within the flange a chamberI20which is in communication with the main air inlet passage It by wayof a passage provided by ports I30 and I32 in plates I20 and I2?respectively. Chamber H8 outside of the flange I26 is in communicationwith the. atmosphere by way of ports When the apparatus is in theposition shown in Fig. 4 the effective diaphragm area exposed toatmospheric pressure is an annulus, the radial extent of which isrepresented by the distance X. However, as soon as the decrease inpressure in the inlet passage M reaches the predetermined valuesufiic'ient to move the diaphragm downwardly, plate I20 moves away fromthe flange I26 and the area exposed to atmospheric pressure is increasedby the annulus, the radial extent ofv which is indicated at Y. In

other words, when the apparatus as shown is in the position shown inFig. 4 chamber I28 is exatmospheric pressure. This arrangement preventsflutter-or chattering of the diaphragm and 5 the movable contact II2under the influence of slight variations in pressure in the intakepassage I4 when the pressure therein is at or near the predeterminedvalue for causing movement .Of the contact.

'I'hespecific manner in which regulation of the length of the strokes ofthe several pumps is effected and the mannerin which the cutting out ofone or more of the pumps is effected is subject to wide variation.

In Figs. 5 to 7 I have illustrated embodiments of such variations inapparatus for controlling the pump unit in accordance with theinvention. The apparatus shown in Fig. 5 is adapted to be used inconnection with electrically actuated means and comprises a fixedinsulated contact I04a and a movable contact II2a which instead of beingactuated by pressure responsive means 7 is mechanically connected to thethrottle actuating means 22 by means of the 25 spring arm I36. As willbe evident from the drawings, contacts I04a and I I2a will be brought-into contact to close the electric circuit and .energize the actuatingmeans such as solenoid I00 in Fig. 1 upon movement of the throttle-to apredetermined position.

Fig. 6 illustrates an arrangement whereby actuation of the pump controlmechanism to cut out certain pumps is effected through the medium of thesuction produced in the engine intake I4. In this arrangement a pistonI38 in cylinder I40 is connectedfto the shaft 18 of the pump unit B bymeans of the lever arm I42.

Chamber I44 in cylinder I40 below piston I38 is connected throughconduit I46 to the engine 40 intake passage I4 under the control of avalve I48 adapted to be actuated by pressure responsive apparatuscomprising diaphragm structure indicated at IIS and preferablyconstructed in accordance with the arrangement shown in Fig.

I 4. The chamber I50 above piston I38 is in com- .munication with theatmosphere and the piston.

is normally moved upwardly by spring I52, the

arm I42 being biased by spring I54.-

From the drawings it will be evident that the 50 arrangement works ingeneral in the same manner as the arrangement shown in Fig. l to causethe shaft 18 to be turned in counter clockwise direction so as to cutout the desired number.

of pumps when a predetermined pressure is produced in the intake passageI4 due to throttling. When the pressure in passage I4 is above thepredetermined value, valve I48 is closed under the influence of spring II4 and spring I52 maintains piston I38 in the position shown in Fig.

80 6, in which, position of the piston the shaft 18 70 associatedsleeves "80 to .a position such that the plungers of the pumps desiredto be cut out of contact with the tappets 54 in any position of thelatter.

Fig. '7 illustrates a wholly mechanical arrange- 75, ment forcontrolling throttling of the air and.

.cordance with intake pressure.

for efiecting regulation and control oi the pumps in the pump unit B.The throttle valve 20 and the pump regulating shaft 62 are connected bymeans of suitable levers I58 and I60 and links I62 and I64 to one armI66 of a bell crank lever, the other arm I68 of which is connected bymeans of a suitable link or rod I10 to a manually operable pedalmechanism indicated generally at I12.

A lever I14 fixed on shaft 18 of the pump unit is connected by means ofrod I16 to a pivoted lever: I18. Rod I16 at one end is pivotallyconnected to one arm of the lever I18 and at its opposite end passesloosely through a hole in the end of lever I14 to provide a lost motionconnection between this lever and rod I16. The end of the lever I18.opposite the end to which rod I16 is attached rests upon the extensionI66a of arm I66 of the bell crank lever.

The operation of the above described form of apparatus is more or lessobvious from the drawings. With pedal I12 in depressed position asindicated in',the drawings, throttle 20 is in open position and theshaft 62 is in a position of rotation such that full stroke of the pumpplungers is permitted. With the apparatus in this position the shaft 18is free insofar as the control apparatus is concerned, to turn inclockwise direction to its limiting position under the influence of asuitable retracting spring I80 so that the sleeves 80 associated withshaft 18 will be out of contact with the pump plungers. As the controlpedal is permitted to riseunder the influence of its retracting spring,links I62 and I64 are lifted by movement of the bell crank lever toeffect closure of the throttle and simultaneous movement of shaft 62 inclockwise direction to decrease the amount of fuel supplied by the pumpunit. Closing movement of the controlpedal from a position correspondingto full load operation to a position corresponding to part loadoperation with throttled admission of air has no effect upon theposition of shaft 18 due to the lost motion connection between lever I14and rod I16. As the throttle is closed and the shaft I62. is moved toeffect decrease of the fuel supply by upward movement of the bell crankarm I66 and links I64 and I62, the

lever I18 is moved in counterclockwise direction as seen in Fig. 7, androd I 16 is moved down!- wardly. Downward movement of rod I16 from theposition shown in the figure has no effect on the position of shaft 18until the enlarged head I16a of this rod makes contact with the end oflever I14 and the length of rod I16 is made such that shaft 18 is notturned in counterclockwise direction from the position shown in thefigure to a position effecting cutting out of the desired pumps untilthrottle 20 is moved to the predetermined position where it is desiredthat one or more of the pumps be cut out of action.

In order to positively limitthe minimum pressure which can be obtainedin the inlet passage I4, auxiliary air openings may be employed. Thesemay be either independent or combined with the apparatus for controllingthe fuel supply in ac- For example, ports I30 and I32 may be madesufficiently large for this purpose.

Fromthe foregoing description it will be evident to those skilled intheart that many variations may be employed in the exercise of theinvention, which is to be understood as not limited to the forms ofapparatus herein disclosed.

6 combustion air to the cylinders'of the engine,

'a plurality of fuel pumps for supplying fuel separately to thecylinders of the engine, a

throttle valve for'controlling admission of air to said manifold, pumpregulating means operative in response to decrease in pressure in theinlet manifold to decrease the amount of fuel supplied by said pumps,and means operative in response to the pressure in said inlet-manifoldfor rendering one or more but less than the total number of saidpumpsinoperative to supply fuel when the pressure in the inlet manifold isbelow a predetermined value.

2. Apparatus of the character described comprising a multiple cylinderinternal combustion engine having an inlet manifold for supplyingcombustion air to the cylinders of the engine, a plurality of fuel pumpsfor supplying fuel separately to the cylinders of the engine, a throttlevalve for controlling admission of air to said manifold, pressureresponsive regulating means operative in response to decrease inpressure in the inlet manifold to decrease the amount of fuel suppliedby the pumps, electrical means for. rendering one or more but less thanthe'total number of said pumps inoperative to supply fuel, and pressureresponsive means operative to cause said electrical means to beenergized when the pressure in said inlet manifold is below apredetermined value.

3, In the operation of multiple cylinder internal combustion engines ofthe injection type, the improved method which comprises progressivelythrottling the air supplied in the low load range of engine operation asthe load decreases, supply ing to each of the several cylinderssubstantially the same amount 'of fuel as that supplied to each of theremaining cylinders throughout the range of engine loads in which fuelis supplied to all cylinders-varying the amount of fuel supplied in thelast mentioned range in accordance with variations i-nload on theengine, cutting off the fuel supply to one or more but less than thetotal number of cylinders when the pressure of the throttled air fallsto a predetermined minimum value and supplying fuel to all of thecylinders when the pressure of the air exceeds said predetermined value.

i. In the operation of multiple cylinder internal combustionpengines ofthe injection type, the improved method which comprises progressivelythrottling the air supplied in the low load range of the engine as theload decreases, supplying to each of the several'cylinders substantiallythe same amount of fuel as that supplied to each of the remainingcylinders throughout the range of engine loads above idling load,varying the amount of fuel supplied in the last mentioned range inaccordance with variations in load on the engine, and cutting 0d thefuel supply to one or more but less than the total numberof thecylinders in' response to decrease in the'pressure of the throttled aircorresponding t idling load.

5. Apparatus of the character described comprising a multiple cylinderinternal combustion engine having an inlet manifold for supplyingcombustion air to the cylinders of the engine; means for injecting fuelseparately into each 'of the cylinders of the engine, means for causingthe first mentioned means -to supply substantially 1 equal amounts offuel at any given load on the engine to each of the several cylinders inoperation at said load, means for throttling the air admitted to saidmanifold and means operative inresponse to a predetermined value ofvacuum of said inlet manifold for cutting off the supply of fuel to oneor more. but less than the total number of said cylinders.

6. That improvement in the operation of a multiple cylinder internalcombustion engine of the injection type which consists in throttling theadmission of air to the engine'to compensate for reduction in engineload, reducing the amount of 'fuel injected to the cylinders of theengine in accordance with reduction in the pressure of the throttled airsupply, limiting the supply of fuel to a pre-determin'ed number ofcylinders less than the total number whenever the "air supply to theengine is throttled to an extent appropriate for idling operation and atany given value of load on the engine supplying substantially likeamounts of fuel to all of the cylinders to which fuel .is then supplied.I I,

7. That improvement in the operation of a multiple cylinder internalcombustion engine of the injection type which consists in controlling.operation of the engine by throttling the admission of air to theengine to compensate for reduction in engine load, reducing the amountof fuel injected to the cylinders of the engine in response toreduction' in the pressure of the throttled air supply, limiting thesupply of fuel to a pre-determined number of cylinders less than thetotal number whenever the engine is throttled to an extent appropriatefor idling operation and at any given value of load on the enginesupplying substantially like amounts of fuel to all of the cylinders towhich fuel is then supplied.

8. That improvement in the operation of a multiple cylinder internalcombustion engine of the injection type which consists in throttling theadmission pf air to the engine to compensate for reduction in engineload, reducing the amount of fuel injected to the cylinders of. theengine in accordance with reduction in the pressure of the .throttledair supply, cutting off the supply of fuel suddenly and substantiallysimultaneously 'to a pre-determined number of cylinders less than thetotal number whenever the engine is throttled to an extent appropriatefor substantially'idling operation of the engine and at any given valueof load'on, the engine supplying substantially like.

amounts of fuel to all of the cylinders to which means for injectingfuel separately into each of the cylinders of the engine, means forcausing the first mentioned means to supply substantially like amountsof fuel at any given load. on the engine to each of the cylinders towhich fuel is then supplied, means for throttling the air admitted tosaid manifold and means for automatically limitingthe supply of fuel toa predetermined fixed number of cylinders less than v the total numberof cylinders whenever the air is throttled toan extent appropriate foridling operation of the engine.

1t. Apparatus of the character described comprising a multiplecylinderinternal combustion combustion air to the cylinders of theengine, means for injecting fuel separately into each of the cylindersof the engine, means for causing the engine having an inlet manifold forsupplying first mentioned means to supply substantially like amounts offuel at any given load on the engine to each of the cylinders to whichfuel is 11. Apparatus of the character described'com-.

prising a multiple cylinder internal combustion engine having an inletmanifold for supplying combustion air, a throttle for controlling flowof air through said manifold, means responsive to variations in thepressure of the throttled air for injecting variable quantities of fuelseparately intoeach of the cylinders of the engine, said means,supplying substantially like amounts of fuel at any given load on theengine to each of the cylinders to which fuel is then supplied and meansfor limiting the supply of fuel to a pre-, determined fixed number ofcylinders less than the total number of cylinders whenever the load onthe engine falls to a value requiring a high de- 'gree of throttling ofthe air to reduce the fuel quantity to an extent appropriate for theload.

12. Apparatus of the character described comprising a multiple cylinderinternal combustion engine having an inlet manifold for supplyingcombustion air, a throttle for controlling flow of air through saidmanifold, means responsive to variations in the pressure of thethrottled air for injecting variable quantities of fuel separately intoeach of the cylinders of the engine, said means supplying substantiallylike amounts of fuel at anygiven load on the engine to each of thecylinders to which fuel is then supplied andmeans actuated upon movementof said throttle to a position providing a highly throttled air supplyto the engine for automatically and substantially simultaneously cuttingoff the supply of fuel to a pre-determined fixed number of cylindersless than the total number of cylinders.

13. Apparatus of the character described comprising a multiple cylinderinternal combustion engine having aninlet manifold for supplyingcombustion air, a throttle for controlling fiow of air through saidmanifold, means responsive to variations in the pressure of thethrottled air for injecting variable quantities of fuel separately intoeach of the cylinders of the engine, said means supplying substantiallylike amounts of fuel at any given load on the engine to each of thecylinders to which fuel is then supplied, electrically actuated meansfor causing the supply of fuel to a pre-determined fixed number ofcylinders less th an the total number of cylinders to be abruptly andsubstantially simultaneously cut off and means operatively associatedwith said throttle for energizing said electrically actuated meanswhenever said throttle is in a position providing a highly throttled airsupply to the engine.

14. Apparatus of the character described comprising a multiple cylinderinternal combustion engine having an inlet manifold for supplyingcombustion air, a plurality of fuel pumps for supplying fuel separatelyto the cylinders of the engine, pump actuating means for causing thepumps to supply substantially like amounts of fuel at any given load onthe engine to each of the cylinders to which fuel is then supplied,throttling means for controlling the fiow of air through said inletmanifold and means operatively associated with said throttling means forrendering a predetermined fixed number of 'pumps less than the totalnumber of pumps inoperative to supply fuel whenever the throttling meansis in a position providing a highly throttled air supply to the engine.

15. Apparatus of the character described comprising a multiple cylinderinternal combustion engine having an inlet manifold for supplyingcombustion air, a plurality of fuel pumps for supplying fuel separatelyto the cylinders of the engine, pump actuating means for causing thepumps to supply substantially like amounts of fuel at any given load onthe engine to each of the'cylinders to which fuel is then supplied,throttling means for controlling the flow of air through said inletmanifold, means responsive to the pressure of the throttled air forgoverning said fuel pumps to reduce the quantity of fuel supplied as thepressure of the throttled air decreases, electrically actuated means forautomatically and substantially simultaneously rendering apre-determined ,fixed number of said pumps less than the total number ofpumps inoperative to supply fuel and means operatively associated withsaid throttling means for energizing said electrically actuated meanswhenever said throttling means is in a position providing a highlythrottled air supply to the engine.

'roRBJoRN VIKTOR DILLs'rRoM.

